This is an approximate and incomplete list of dates that CDs were manufactured. If you can fill in some of the missing information, or correct mistakes, please do so!

This is an approximate and incomplete list of dates that CDs were manufactured. If you can fill in some of the missing information, or correct mistakes, please do so!

-

The Name, Application, and Nickname are mostly from N.R. Woodward's "The Glass Insulator in America" Reports. The Start Date and End Date have three notations -- ">" and "<" which indicate that the date was, respectively, after or before the year given (inclusively), and "~" which indicates approximately. The References state where this information came from, and Comments provides some additional information to help in the dating. The Assigned Date and Comments show when the CD was originally assigned (again, note that this is approximate).

+

* The Trade Name, Application, and Hobby Nickname are mostly from N.R. Woodward's "The Glass Insulator in America" Reports.

+

* The Start Date and End Date have four notations

+

** ">" which indicates the date is as specified or after

+

** "<" which indicates the date is as specified or before

+

** "~" which indicates the date is approximately

+

** dates in italics are our best guess, as opposed to fact based.

+

* The References state where this information came from

+

* Comments provides some additional information to help in the dating.

+

* The Assigned Date and Comments show the date of publication of the first reference showing the CD (again, note that this is approximate).

-

{| style="text-align:center;" border="1"

+

NOTE: Rows in gray deal with CDs that have been deleted, combined with other CDs, or for which there are no known examples.

| align="left" |102.4|| &nbsp;|| Telephone|| &nbsp;|| 1883>|| 1888<|| <ref>CD 102.4 a product of the Lyndeborough Glass Company, South Lyndeboro, New Hampshire (1866-1888). Many shards have been found by a digger at the old glassworks site. Per David Whitten, 10/12/2009 email.</ref>|| Unique to NEW ENG.TEL.& TEL.CO.|| 1976|| [Mil76]

|CD 102.4|| &nbsp;|| Telephone|| &nbsp;|| 1883>|| 1888<|| <ref>CD 102.4 a product of the Lyndeborough Glass Company, South Lyndeboro, New Hampshire (1866-1888). Many shards have been found by a digger at the old glassworks site. Per David Whitten, 10/12/2009 email.</ref>|| Unique to NEW ENG.TEL.& TEL.CO.|| 1976|| [Mil76]

| align="left" |106|| Pony|| Telephone|| Pony|| 1892~|| 1955|| <ref>"The CD 106 Hemingray-9 was introduced in either 1892 or 1893 and continued in production until at least the early 1950's (my example is 1951) until replaced by the CD 107 Hemingray-9 in 1956." Per Bob Stahr, 09/12/2007 email on ICON.</ref><ref>CD 106 Per N.R. Woodward on Hemingray</ref>|| &nbsp;|| 1967|| [NRW67]

| align="left" |121|| Toll|| Telephone|| Toll|| 1880s|| 1935>|| <ref name="woodward20091214a">"CD #121 was the original AT&T long distance style used starting with the first long lines in the 1880s. Until WWI it was esssentially unchanged." N.R. Woodward on ICON, 12/14/2009.</ref>|| Made by STANDARD GLASS INSULATOR CO (1893-1894) and MAYDWELL (1935-1940)|| 1967|| [NRW67]

|CD 121.4|| American Union|| Telegraph|| &nbsp;|| 1871>|| 1893<|| &nbsp;|| Unique to A.U. all have Pat'd 1871. End date based on absence of May 2 1893 patent date.|| 1973|| [GIaCR]

+

| align="left" |124.1|| &nbsp;|| &nbsp;|| &nbsp;|| 1871~|| 1873~|| <ref name="burger20091015">" Hemingray offered their smallest "bullet", the CD 124.1 probably as early as the 1871 Patent they wear. It is believed the 124.2 superseded the .1 as early as 1873, with the 124.3 being offered by about the time the very first Brookfield produced "pony" was introduced in the July, 1878 Tillotson catalogue." Brent Burger in ICON 2009.10.15 digest.</ref>|| Unique to PATENT - DEC. 19 1871 || &nbsp;||

| align="left" |129|| TS Carrier|| Telephone|| &nbsp;|| 1954|| 1975<|| <ref>CD #129 should have a date of 1954. First ones were made that year by both Owens and Armstrong. The single-page brochure I have advertising the "TS" as a "new insulator" has a print date of 1955. Per N.R. Woodward on ICON, 10/16/2009</ref><ref>End date based on Kerr production.</ref>|| 1967|| [NRW67]

|CD 129|| TS Carrier|| Telephone|| &nbsp;|| 1933>|| 1975<|| &nbsp;|| Start date based on use of mold numbers by Hemingray end date based on Kerr production. All other embossings fall in this range.|| 1967|| [NRW67]

| align="left" |136.4|| &nbsp;|| Telegraph|| Canadian Boston|| 1879<|| 1872>|| <ref>The versions with segmented threads are through to have been made by Boston Bottle Works, or Bay State Glass Works, active from 1872-1879. See http://cjow.com/archive/article.php?month=8&a=08Patent%20Pages.htm&year=1979 , http://cjow.com/archive/article.php?month=9&a=09Samuel%20Oakman%20and%20Boston%20Insulator%20Production.htm&year=1988 , and http://cjow.com/archive/article.php?month=6&a=06Boston%20Family%20Album.htm&year=2004</ref>|| NO EMBOSSING or NO NAME|| 1976|| [Mil76]

| align="left" |143|| Dwight Pattern|| Telegraph|| &nbsp;||<I>1875</I>||<I>1906></I>||<ref>Unsure when Canadian glass houses started using threads, but likely in the 1870s. All Dwight Patterns are thought to be Brookfield products, but were never made in Old Bridge colors. This implies these stopped being made by 1906. Other CD 143s could have been made later.</ref><ref>per Barret Nicpon, 8/15/2016 on ICON: As far as the Dwight CD-143 use era, I would suggest that a general

+

turn-of-century window is probably appropriate for these pieces. This isn't

+

based on any written or historical data, but rather on my own digging

+

experience. They seem to have begun to be used sometime in perhaps the

+

mid-to-late 1890s, and their use was probably truncated by the beginnings

+

of G.N.W. TEL. CO. CD-145 production. These seem to have been in prolific

+

use by the early 1900s. I can't personally offer much assurance on the

+

accuracy of these dates, unfortunately.

+

+

As far as the use of threadless in Canada goes, I believe the magic date

+

for the switchover to threaded glass took place around 1875-1877, depending

+

on the company and individual line. Again, this is based on my own personal

+

experience of line construction dates compared with digging finds. This is

+

also based on correspondence with other collectors who have indicated

+

threadless glass can be found on even newer lines on rare occasions. This,

+

I assume, is an example of a frugal line superintendent or telegraph

+

company continuing to re-use new-old-stock insulators into more modern

+

eras. Overwhelmingly, it seems threadless were no longer being used by the

+

beginning of 1877 and had been replaced by early 143s, such as threaded

|CD 204|| Transposition|| Telephone|| Locke Crosstop or Tramp|| 1892|| 1895|| Per Locke biography.|| LOCKE (1892-) or NO EMBOSSING Pat'd 1894. NO EMBOSSINGs made first around 1892 only manufactured for a short while.|| 1973|| [GIaCR]

| align="left" |342|| &nbsp;|| 25 000v|| &nbsp;|| 1903|| 1903|| <ref>CD 342s were made in a single production run in late 1903. The very first CD 342 tops had no embossing and were likely prototypes made before the embossing was engraved. Note that unembossed bases were produced May - December, 1900 for the M-2795 gutter tops. CD 342s with unembossed bases are reconstructed from a CD 342 top and a M-2795 bottom. Per correspondence with Mike Spadafora, 10/29/2010.</ref>|| Unique to LOCKE (1892-)|| 1967|| [NRW67]

Notes

↑ CD 102.4 a product of the Lyndeborough Glass Company, South Lyndeboro, New Hampshire (1866-1888). Many shards have been found by a digger at the old glassworks site. Per David Whitten, 10/12/2009 email.

↑ "The CD 106 Hemingray-9 was introduced in either 1892 or 1893 and continued in production until at least the early 1950's (my example is 1951) until replaced by the CD 107 Hemingray-9 in 1956." Per Bob Stahr, 09/12/2007 email on ICON.

↑ "CD #121 was the original AT&T long distance style used starting with the first long lines in the 1880s. Until WWI it was esssentially unchanged." N.R. Woodward on ICON, 12/14/2009.

↑ "CD #122 came along in 1919-20, the change in design was the larger square wire groove; and corresponding greater outward slant to the skirt and slightly greater base width" N.R. Woodward on ICON, 12/14/2009.

↑ 10.010.110.2 " Hemingray offered their smallest "bullet", the CD 124.1 probably as early as the 1871 Patent they wear. It is believed the 124.2 superseded the .1 as early as 1873, with the 124.3 being offered by about the time the very first Brookfield produced "pony" was introduced in the July, 1878 Tillotson catalogue." Brent Burger in ICON 2009.10.15 digest.

↑ CD #129 should have a date of 1954. First ones were made that year by both Owens and Armstrong. The single-page brochure I have advertising the "TS" as a "new insulator" has a print date of 1955. Per N.R. Woodward on ICON, 10/16/2009

↑ Unsure when Canadian glass houses started using threads, but likely in the 1870s. All Dwight Patterns are thought to be Brookfield products, but were never made in Old Bridge colors. This implies these stopped being made by 1906. Other CD 143s could have been made later.

↑ per Barret Nicpon, 8/15/2016 on ICON: As far as the Dwight CD-143 use era, I would suggest that a general
turn-of-century window is probably appropriate for these pieces. This isn't
based on any written or historical data, but rather on my own digging
experience. They seem to have begun to be used sometime in perhaps the
mid-to-late 1890s, and their use was probably truncated by the beginnings
of G.N.W. TEL. CO. CD-145 production. These seem to have been in prolific
use by the early 1900s. I can't personally offer much assurance on the
accuracy of these dates, unfortunately.
As far as the use of threadless in Canada goes, I believe the magic date
for the switchover to threaded glass took place around 1875-1877, depending
on the company and individual line. Again, this is based on my own personal
experience of line construction dates compared with digging finds. This is
also based on correspondence with other collectors who have indicated
threadless glass can be found on even newer lines on rare occasions. This,
I assume, is an example of a frugal line superintendent or telegraph
company continuing to re-use new-old-stock insulators into more modern
eras. Overwhelmingly, it seems threadless were no longer being used by the
beginning of 1877 and had been replaced by early 143s, such as threaded
743.x, Montreal Telegraph CD-143s, and other unembossed 143s.

↑ CD 143.4 McDougald's states that manufactured at similar time to CD 145

↑ CD 145 Probably first made by AMERICAN. Hemi clear units made at least until 1947.

↑ The Rainbow Riders' Trading Post, June 15, 1995. Vol. 4, No. 6, p9. "The Millville Report" by Richard Wentzel. "...figures A, B, and C verify production of 1,241 pieces during trial automated production from April 12 through April 17, plus 882 pieces produced on June 7, for a total of 2,133, plus an unspecified amount produced on April 6."

↑ CD 342s were made in a single production run in late 1903. The very first CD 342 tops had no embossing and were likely prototypes made before the embossing was engraved. Note that unembossed bases were produced May - December, 1900 for the M-2795 gutter tops. CD 342s with unembossed bases are reconstructed from a CD 342 top and a M-2795 bottom. Per correspondence with Mike Spadafora, 10/29/2010.